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  1. #1
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    Exclamation EchoMap Plus 95sv - side scan streaks and jagged waves

    So I went to a lake this weekend, and this was the first time using my EM+ 95sv on it. DownVu and 2D sonar seem perfectly normal, but my side scan images concerned me. I am concerned I have a transducer gone flaky on me. It is supposed to start raining tomorrow and then for a few days so after that I will go to my main lake to see what I see. Or could the lake structure cause this? I'll explain more on the lake structure later.

    Look at these images and notice the streaked lines, which are very apparently on the left side scan, but do also show up sometime on the right side scan. In one image I think I lowered the power level, thus why the image got darker.
    26JUN20_2039_00.bmp
    26JUN20_2127_00.bmp
    27JUN20_2028_00.bmp
    27JUN20_2031_00.bmp

    And look at these. I'm thinking these are sand ripples, but look at how jagged they are:
    27JUN20_1209_00.bmp
    27JUN20_1918_00.bmp

    Now, the very vast majority of the portions (of this lake) that I travelled are between 0.5 to 3.0 meters, and the rocks are very very rough, with sharp edges. Is there any chance the transducer is simply receiving a lot of echos that bounce and split off the rocks, thus 'loud but not clean' returns (to use those words), or does this look like a transducer gone bad? I got the thing for Christmas so hopefully the warranty applies; a quick google search shows 1 year.

    Seems like the more you zoomed out the worse it got. I set the power levels on the side scan to "auto low" but it didn't seem to matter. Maybe I should have used the manual power settings.

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    #2
    were you on choppy water at all?

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    #3
    No, but I am in a peddle drive kayak. When the water is choppy/waves I see ripples in the down imaging too. And if the kayak turns I get circular streaks in the side scan. I could see how waves could cause the jagged ripples, but not those straight line streaks. This lake is very shallow and very flat. I looked at some side scan pictures from the very first pictures I took and I see the same thing only its way less noticeable. I assume that is because of (a) deeper water and (b) stones that are smoother.

    I am in a kayak, so I do around 2 -3 KMh, and I have the side scan speed set to auto. It seems to work pretty good, and I don't think I am going too slow. I do/did get decently nice images from this thing. Those straight line streaks make me think it's like every so often the ping is of extra power so it shows up brighter. I'm using a 75Ah Group 24 deep cycle battery and my wiring is a bit larger than the Garmin wiring. I always recharge the battery after each day, and the FF screen never shows lower than 12.4v.

    Todd if you are reading this would be nice to hear from you or Garmin.

    Weather forecast looks like no rain for a couple hours so I am going to try to get to the lake again this morning to see if I get the same kind of images before, or if the images are worse like from this weekend pond.

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    #4
    UHD image, the lines are hard to see on the left side scan but on the 6th attached image they are there between 100 and 125 feet:
    http://www.bbcboards.net/showthread.php?t=1004721

    This one is easier to see. Really looks like the same sort of lines I am seeing. His are angled a slight bit, but seem to be the same sort of straight streaks (slight brighter streaks), spaced fairly the same distance apart. Look at the first image in this thread, the left side scan, between 35 and 50 feet:
    http://www.bbcboards.net/showthread.php?t=1022354


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    #5
    have you tried taking speed off of Auto to see what happens?

    Kayaks have strange effects on sonar.

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    #6
    here’s one from a Lowrance
    Attached Images Attached Images

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    #7
    Can't see how a kayak would affect a sonar, other than the kayak being wobbly. Mine is really steady with the pedal drive, and the transducer is mounted low enough that no part of the kayak or peddle drive should interfere with any of the sonar energy. That Lowrance image seems to have to the same lines, but they are vertical instead of horizontal. Those pictures I posted from other thread on this board are not kayaks I'm pretty sure.

    I can try setting the side scan speed to a really low number. I was using auto, that seemed to work best. Might be able to try this evening, or Canada Day this coming Wednesday.

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    #8
    I would guess most manufacturers dont test their units with kayaks, except maybe for something like an Echomap 4 series.

    Kayaks move around much more than a larger boat. Theyre more susceptible to wave effects in all directions. And maybe a pedal drive emits a type of vibration that can affect sonar.

    If you’re seeing odd lines on yours and I am too, it has to be considered.

    I have more screenshots of different units on a kayak and will look at them when im back home from my work trip.

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    #9
    Quote Originally Posted by Chief Brody View Post
    And maybe a pedal drive emits a type of vibration that can affect sonar.
    I went to a different pond today, and played with a few settings, and then I remembered you saying this. So I peddled pretty fast, and the lines got so close you almost could not see them. Then I stopped peddling and they completely disappeared. Then it struck me, I was peddling really slow at the other pond because it was so shallow and I did not want to hit a rock and snap off one of the flippers like I already did last year.

    But it is happening more just the same. And then I got to thinking, the manufacture sent me a new drive system that uses different types of rods inside the flippers; they are like shear pins now. So, it seems you nailed it. Somehow the peddle drive does seem to affect the sonar. The weird thing is the lines are on the left side, and the 'ducer' is to the left of the peddle drive. I would expect the right side to be affected more. I'll have to scratch my head on that a bit. Or just relocate the ducer and go fishing. Or just live with it, since the ducer is in the perfect place to lift it up if I suddenly come upon some rocks.

    Thanks everyone. :-)

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    #10
    What kayak and drive do you have? If you dont mind me asking

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    #11
    I have a 2019 Pelican Catch 130HD. This year Pelican sent me a free upgrade to the Gen2 Hydrive on the condition I send back the Gen1 drive. So I did. The new drive has shear pin rods in the flippers, instead of regular rods. The Gen1 rods were hollow with some sort of plastic filler. I have not (yet) snapped off a new shear pin rod to be able to say what is inside the rod.

    It is a fantastic kayak I must say, and around 36Kg, is easy to lift up into the back of a truck. I got lots of weight in it (me, anchor, 40lbs deep cycle battery for the Garmin, a crate full of food and water, and a tackle box the size of a file cabinet, and it floats just fine.) That just said, when out bass fishing, after peddling 13+ kilometres over 8 hours in the hot sun......I think I am gonna sell it and get a 12-16 ft jon boat with engine. I'm not 22 anymore. :-)

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    #12
    Nice ��

    Actually im a little surprised that the Hobie-style drive would mess with your imaging. I was assuming you had a prop type drive that made gear noise as you peddled.
    I just got another mount in for my Hobie and might get out this weekend with it and a fishfinder. Ill try to get some images to see if im getting the lines too.

    That pic earlier was a different paddle-only yak.

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    #13
    I'm guessing the transducer gets a lot of feedback from the 'immediate' water surrounding it, and the electronics/software to a bunch of filtering for that. I'm also guessing that somehow the flippers when they move are like moving 'sound mirrors' and the software doesn't catch it.

    I had assume that I was one of the very few on this board that was a kayak user. Just assumed everyone else was running a top-fuel American dragster style bass boat. :-)

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    #14
    Well I was out today in the Hobie and a gen3 HB Mega+
    other than the usual spikey up and down lines from waves, there was nothing else of note

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    #15
    I have since been on a few other ponds, and the very short story version, is shallow water I see lines when I peddle slow. Peddle fast, and/or deeper water and the lines are either gone or so faint you can't really see them.